A. Field of the Invention
This invention relates to pads and pillows for comfortably supporting parts of the human body. More particularly, the invention relates to an adjustable cervical pillow for supporting the head and neck at adjustable relative positions.
B. Description of Background Art
A variety of pillows and pads for supporting the head, neck and other parts of the body are known. For example, pillows having a soft fabric cover and filled with a soft, yielding material such as feathers or down have long been in use. More recently, synthetic filler materials such as polyester fibers have been used as an alternative to down or feathers.
Usually, it is preferable that a pillow provide more support in the neck area than in the head area. Thus, health core professionals have found that a higher degree of neck support relative to head support helps to relieve pain and improve the rate of healing of certain injuries, owing to a reduction in mechanical stress on the muscles, tendons, nerve roots and other soft tissue structures in and around the spinal column.
To provide different degrees of support for the head ant neck, some prior art pillows have been constructed using fillers consisting of synthetic fibers (fiber fill), feathers, or down of various densities and fullness, with special shapes formed in the pillow, usually by sewing the cover to form hollow sections or compartments. However, pillows of this type are not adjustable to suit different users, or for treating different problems, Also, pillows having a fixed configuration generally do not allow the flow of filler material from areas on which high external pressures are imposed by the body, to lower pressure areas which are more lightly loaded by different parts of the body.
Another type of prior art pillow intended to provide varying degrees of support for the head and neck utilizes a foam rubber core of a selected resilience, pre-formed to a desired shape and size. Some pillows of this type employ replaceable foam inserts. A disadvantage of foam pillows of this type is that they generally must be custom-made to fit different individuals. Also, foam filled pillows tend to compress more in high pressure areas.
Another type of prior art pillow utilizes an inflatable bladder. While such pillows are adjustable in size, they are usually uncomfortable, and have a steep gradient in supporting force from portions of the body contacting the pillow to unsupported portions.
Prior art pillows have also been constructed utilizing a flowable inner filling such as polystyrene beads. Pillows of this type tend to be comfortable, since they conform readily to the contours of the user. However, pillows of this type sometimes may not be supportive enough in the neck area for certain conditions or users, particularly if made into larger sizes for use by larger individuals.
Other types of adjustable pillows known to the present inventor include those described in the following U.S. Patents: